A gas turbine generally includes a compressor section, a combustion section, a turbine section, and an exhaust section. The compressor section progressively increases the pressure of a working fluid entering the gas turbine and supplies this compressed working fluid to the combustion section. The compressed working fluid and a fuel (e.g., natural gas) mix within the combustion section and burn in a combustion chamber to generate high pressure and high temperature combustion gases. The combustion gases flow from the combustion section into the turbine section where they expand to produce work. For example, expansion of the combustion gases in the turbine section may rotate a shaft connected, e.g., to a generator to produce electricity. The combustion gases then exit the gas turbine via the exhaust section.
The turbine section includes a plurality of turbine rotor blades, which extract kinetic energy and/or thermal energy from the combustion gases flowing therethrough. These rotor blades generally operate in extremely high temperature environments. In order to achieve adequate service life, the rotor blades typically include an internal cooling circuit. During operation of the gas turbine, a cooling medium such as compressed air is routed through the internal cooling circuit to cool the rotor blade. Nevertheless, the conventional cooling circuit arrangements may produce undesirable thermal gradients in the rotor blade or otherwise insufficiently cool the rotor blade. Accordingly, a rotor blade having a cooling circuit that does not produce undesirable thermal gradients would be useful in the art.